Energy Efficient Fenestration Assembly

ABSTRACT

A fenestration assembly comprising a sliding glass assembly that slides between a fully closed position and a fully open position in which the sliding glass assembly is received into a pocket of the fenestration assembly. The pocket is covered on at least one side with insulation. The fenestration assembly may have two sliding glass assemblies. The fenestration assembly may be used in an energy efficient building system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/421,028 entitled Energy Efficient Fenestration Assembly filed 11 Feb.2015 which is a National Phase of Patent Cooperation Treaty ApplicationNo. PCT/CA2013/000703 entitled Energy Efficient Fenestration Assemblyfiled 12 Aug. 2013 which further claims priority from U.S. patentapplication Ser. No. 13/572,625 filed 11 Aug. 2012 entitled BuildingEnergy System. patent application Ser. Nos. 14/421,028 andPCT/CA2013/000703 are each a continuation-in-part of patent applicationSer. No. 13/572,625. The subject matters of the prior application areincorporated in their entirety herein by reference thereto.

FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

None.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to fenestration assemblies for both new andretrofit construction and in particular to energy efficient fenestrationassemblies.

2. Background

Over the past forty years, the energy efficiency of windows has beensignificantly improved. One key technological improvement has been thedevelopment of low-emissivity coatings with sputtered low-e coatingsoffering the highest performance. Generally, there are two main types ofsputtered coatings: solar control and solar gain. Comparing the twocoatings, the emissivity of the solar control coating is lower resultingin reduced heat loss. However in a comparison study by the NationalResearch Council of Canada using side-by-side test house monitoring, thestudy showed that with solar gain low-e coatings overall building energyconsumption is 10 per cent lower because of higher direct solar gainsduring the heating season. Although during the cooling season because ofhigher solar gains, building energy consumption is higher with solargain low-e coatings.

Typically because of durability concerns, high performance sputteredcoatings have to be located on the cavity glass surfaces of aninsulating glass unit. However recently, more durable sputtered low-ecoatings have been developed that can be used on exterior surfaces andby adding an exterior low-e coating to the outer interior surface of adouble glazed unit, center-of- glass insulating performance is typicallyincreased from R-4 to R-5.

Vacuum insulating glass (VIG) is an energy efficient window product thatcan provide outstanding center-of-glass insulating performance. Withvacuum insulating glass, there is minimal heat loss through convectionor conduction across the small vacuum cavity and the main heat losssource is through radiation. By using an ultra low emissivity coating,radiation heat loss can be reduced to a minimum and this can provide forR-15 center-of-glass performance for a double-glazed unit. However witha high performance solar control coating on surface two (glazingsurfaces numbered from the exterior), direct solar heat gains throughsouth-facing windows can be substantially reduced during the heatingseason and this lowers overall window energy performance.

As well in order to maintain the vacuum within the VIG unit, the twoglass sheets are fused together at the edge resulting in a substantiallylower R-value around the perimeter edge, for example about R-1. If theVIG unit is installed in a conventional window frame, R-valueperformance is further downgraded and so despite the impressivecenter-of-glass R-value performance, overall window performance is notsubstantially higher than with a conventional double glazed window.

SUMMARY OF THE INVENTION

In accordance with the present disclosure, there is provided afenestration assembly for enclosing an opening in a building wall, thefenestration assembly comprising: a frame having at least four edgessurrounding first and second sides to be partially covered by buildingmaterial, the frame defining: an opening from the first side to thesecond side; and a first pocket section next to the opening and sized atleast equally to the opening; an insulating section between the firstpocket section and one of the first or second sides of the frame; and afirst sliding glass assembly within the frame capable of sealing theopening and moveable between: a fully- closed position in which thefirst sliding glass assembly is located substantially within the openingand seals the opening; and a fully-open position in which the firstsliding glass assembly is located substantially within the first pocketsection of the frame.

In accordance with the present disclosure, there is further provided 46.A building energy system comprising: a building enclosure having aninterior and exterior, the building enclosure comprising at least onewall separating the interior and exterior and comprising an opening; afenestration assembly enclosing the opening in the wall, thefenestration assembly comprising: a frame having at least four edgessurrounding first and second sides partially covered by buildingmaterial, the frame defining: an opening from the first side to thesecond side; and a first pocket section next to the opening and sized atleast equally to the opening; an insulating section between the firstpocket section and one of the first or second sides of the frame; and afirst sliding glass assembly within the frame capable of sealing theopening and moveable between: a fully-closed position in which the firstsliding glass assembly is located substantially within the opening andseals the opening; and a fully-open position in which the first slidingglass assembly is located substantially within the first pocket sectionof the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a description by way of example of certain embodimentsof the present invention, reference being made to the accompanyingdrawings.

FIG. 1 shows a perspective view of a fenestration assembly thatincorporates a pocket window frame and a horizontal sliding, vacuuminsulating glass (VIG) unit and that moves back and forth into a cavitythat forms part of the pocket window frame.

FIG. 2 shows an elevation view of a fenestration assembly as shown inFIG. 1 with the horizontal VIG unit in a half open positioned.

FIG. 3 shows a horizontal cross section on a line 2 a-2 a of thefenestration assembly as shown in FIG. 2.

FIG. 3a shows a horizontal cross section detail of the VIG unit as shownin FIG. 3.

FIG. 4 shows a vertical bottom edge cross section detail on a line 2 b-2b of the fenestration assembly as shown in FIG. 2.

FIG. 5 shows a vertical bottom edge cross section detail on a line 2 c-2c of the fenestration assembly as shown in FIG. 2.

FIG. 6 shows a perspective detail of the ball bearing roller cart forthe horizontal sliding, VIG unit as shown in FIG. 1.

FIGS. 7a, 7b, 7c, 7d show alternative vertical plan and bottom edgecross section details of a compression sealing and push-over operationfor a horizontal sliding VIG unit as shown in FIG. 1.

FIG. 8 shows a horizontal cross section of the horizontal sliding VIGunit as shown in FIG. 1 with a complementary compression sealing andpush-over operation to the top and bottom compression and sealing deviceas described in FIG. 7.

FIGS. 9a, 9b, 9c, 9d, 9e, 9f show a series of vertical cross sectionsand related details of the fenestration assembly as shown in FIG. 1overlapping a traditional single hung window and installed on theinterior side of a masonry wall retrofitted with additional insulationand where the fenestration components including a Venetian blind arepositioned in different seasonal modes of operation.

FIG. 10 shows an elevation view of a fenestration assembly thatincorporates a pocket window frame and two horizontal sliding, doubleglazed sash windows that move back and forth into two cavities that formpart of the pocket window frame and where the fenestration assembly alsoincorporates a Venetian blind located between the sliding VIG units.

FIG. 11 shows a vertical cross section detail on a line 10 a-10 a of thefenestration assembly as shown in FIG. 10 installed within a 2″ by 6″wood stud wall and with overlapping rigid insulation.

FIG. 12 shows a vertical cross section on a line 10b-10b of thefenestration assembly as shown in FIG. 10 installed within a 2″by 6″wood stud wall and with overlapping rigid insulation.

FIGS. 13a, 13b, 13c, 13d show a series of vertical diagrammatic crosssections on a line 10 a-10 a of the fenestration assembly as shown inFIG. 10 with the sliding, sash units and the Venetian blind in differentseasonal modes of operation.

FIG. 14 shows a shows a schematic diagram of a building energy systemfeaturing a dynamic, high-R fenestration assembly as described in FIG.10.

DETAILED DESCRIPTION

Referring to the drawings, FIG. 1 shows a perspective view of afenestration assembly 25 incorporating an opening 26 and a horizontalsliding glazing sub assembly 27 that overlaps the opening 26 in a closedposition. As shown by the arrow 28, the glazing sub assembly 27 can moveback and forth into a cavity pocket 29 that is located on one verticaledge 30 of the opening 26. The cavity pocket 29 forms part of a pocketframe 31 that is also comprised of an outer frame sub assembly 38 thatsurrounds both the opening 26 and the cavity pocket 29. Insulating walls36 (not shown), 37 are located on either side of the cavity pocket 29and are attached to the outer frame sub assembly 38. Insulating mullions51 (not shown), 52 are located adjacent to the vertical edge 30 and arespaced apart to form a slot 42. Insulating inserts 45 (not shown), 46are located on the other three edges 47, 48, 49 of the opening 26 andoverlap the glazing sub assembly 27 when the sub assembly 27 is in aclosed position.

Specifically the glazing sub assembly 27 as shown in FIG. 1 is a vacuuminsulating glass (VIG) unit 39. Although the insulating performance ofthe VIG center-of-glass 66 can be as high as R-15, the insulatingperformance of the VIG perimeter edges 35 is poor, typically about R-1.When the VIG unit 39 is in a closed position, the conductive perimeteredges 35 are buried within the three insulating edge pockets 32, 33, 34and the insulating mullion edge pocket 89 that forms part of the cavitypocket 29. As a result, perimeter heat loss is substantially reduced andoverall energy performance is enhanced.

The outer sub frame 38 of the pocket frame 31 is typically fabricatedfrom narrow hollow profiles 43 that can be made from a variety ofmaterials, including: fiberglass, polyvinyl chloride (PVC), PVC foam andthermally broken aluminum. Depending on the framing material used,various techniques can be utilized to join the sub frame profiles 43 atthe corners 44. No specific jointing technique is shown in FIG. 1.Insulating walls are located 36, 37 on either side the cavity pocket 29and can be attached to the outer frame using various means and again nospecific technique is shown in FIG. 1.

On the interior side, the insulating inserts 46 and insulating mullioninserts 52 are removable and this allows the VIG unit 39 to be taken outas required for repair or replacement. The insulating inserts 45 (notshown), 46 and mullions 51 (not shown), 52 can be made from variousinsulating material combinations, including: PVC hollow profiles PVCfoam with an integral skin and foam-filled fiberglass pultrusions.Depending on the material combination used, various jointing techniquescan be utilized to attach the insulating inserts 45(not shown), 46 andmullions 51(not shown), 52 to the outer frame sub assembly 38 and to theinsulating walls 36(not shown), 37 of the cavity 29.

A slim line U-channel profile 54 is adhered the perimeter edge 35 of theVIG unit 39 using sealant material (not shown). Part of the lockingmechanism (not shown) is attached to the stile profile 54 while thecomplementary cam lock (not shown) is attached in part to the outerframe 38. Typically, a collapsible handle or finger pull (not shown) isdirectly attached to the VIG unit 39.

As shown by arrow 28, the VIG unit 39 can be moved horizontally back andforth either manually or through a motorized process that typicallyinvolves a motor in a fixed location with various mechanical means usedfor moving the unit back and forth, including: ball screws, cog tracks,cables, rotary handles and the like.

Typically, the fenestration assembly 25 is prefabricated in a factory tostrict quality standards. Specifically edge joints 64 in the pocketframe 31 are carefully sealed and this helps ensure that when thefenestration assembly 25 is retrofitted to the interior side of abuilding opening, there is no air leakage to the outside and when thefenestration assembly 25 is retrofitted to the exterior side of abuilding opening, there is no water penetration to the inside.

After the fenestration assembly 25 has been installed in a building,removable window trim (not shown) can be added. The removable trim isjoined together at the corners with special connectors (not shown). Oneoption is for the removable trim to be made from PVC foam material andby overlapping the removable inserts 46 and removable mullion insert 52.The PVC foam window trim provides additional edge insulation thatfurther prevents perimeter heat loss. In addition, the window trim canprovide for additional structural rigidity for the slot mullion assembly42.

Although a VIG unit 39 is shown in FIG. 1, other types of slidingglazing sub-assemblies can be substituted including: conventionalinsulating glass units, laminated glass sheets, window sashes and patiodoors.

FIG. 2 shows an elevation view of the fenestration assembly 25 asdescribed in FIG. 1 with the horizontal sliding VIG unit 39 in a halfclosed position. When the VIG unit 39 is in a closed position, thepocket frame 31 overlaps all four sides 47, 48, 49, 50 of the VIG unit.The perimeter edge 35 of the VIG unit 39 is shown by the dotted line 41.

FIG. 3 shows a horizontal cross section detail on a line 2 a-2 a throughthe fenestration assembly 25 as shown in FIG. 2 with the horizontalsliding VIG unit 39 in a fully closed position. In a fully openposition, the VIG unit 39 is received within a cavity pocket 29.

The insulating walls 36, 37 on either side of the cavity pocket 29 canbe made from various insulating materials with one option being astressed skin panel assembly 61 consisting of an insulating inner core62 adhered to outer structural sheets 63. The insulating core 62 of thestressed skin panel 61 can be made from a variety of plastic foammaterials with polyurethane, and extruded or expanded polystyrene beingsuitable materials. In case of expanded polystyrene, the foam materialmay be fabricated in large blocks and precut to size using CNCequipment.

The structural skins 63 can be made from a variety of structural sheetmaterials, including: galvanized steel, cardboard/plastic board, woodsheathing, plywood, glass fiber reinforced sheeting etc. The stressedskin panels 61 are attached to outer frame sub assembly 38 on threesides 58,59,60 (See FIG. 1) and this helps square the outer frameassembly 38 and also helps provide rigidity to the mullion slot assembly42. Depending on the stressed skin panel materials that are used, thewidth of the stressed skin panel 61 can be as little as 0.5 inchalthough for higher insulating performance and increased stiffness itmay be desirable that the panel width is a minimum of 0.75″, or moresuch as 1″ in width. To further improve the insulating performance ofthe cavity portion 78 of the pocket frame 31, one of the cavity wallsurfaces 79 may be covered by foil 80 with a low-emissivity surfacefinish 81.

A further option is for the stressed skin panel 61 to incorporate avacuum insulating panel (VIP) 65 as the center insulating core 62. VIPs65 are typically manufactured from an insulating flat sheet of matrixmaterial that is packaged in a metalized multilayer barrier filmmaterial. The matrix material can be made from various insulatingmaterials with one suitable material being fumed silica. Compared to theother matrix materials, the fumed silica has the advantage that there isno need to incorporate additional desiccant and getter materials. DowCorning manufactures a VIP panel incorporating a silica matrix and thecompany predicts that after thirty years, the product will retain morethan eighty percent of its initial R-35 insulating performance.

To provide for the required structural stiffness, the VIP panel 65 canbe adhered to structural stressed skins 63 and one suitable structuralskin material is galvanized sheet metal. Various adhesives can be usedto adhere the outer structural skins to the VIP panel inner foam corewith one option being acrylic pressure sensitive adhesive. A secondoption is to use dabs of silicone sealant located about 2 to 3 inchesapart and this generally provides for improved long term durability.

When retrofitting the fenestration assembly 25 to the interior wall ofan existing building, it may be desirable that the pocket frame width 82is kept to a minimum in order to ensure that the least amount ofinterior space is lost. Generally for a VIG glazing assembly, 23/4inches is the minimum pocket frame width 82 that is technicallyfeasible. This width includes a pre-applied plaster board 87 (not shown)over the cavity pocket 29.

For a minimum pocket frame width 82 of 2.25 inches, the fenestrationassembly 79 includes: a 0.25 inch wide plaster board 87 (not shown) witha cardboard backing; a 0.75 inch wide insulating stressed skin foampanel 61 with a low-e coating foil 81 that functions as a structuralskin 63 adhered to the foam core 62; a 0.75 inch wide cavity pocket 29for the VIG unit 39, and a 0.5 inch wide VIP panel 65 sandwiched betweenmetal protective sheets 63. The combined R value of the cavity pocketassembly 79 is about R-22 and as described in FIG. 9, this is about thesame as the combined center-of-glass R-value for a VIG unit 39retrofitted to an existing single glazed window and incorporating aVenetian blind assembly.

The hollow frame profile 43 of the outer frame 38 may be made frompolyvinyl chloride (PVC) material and incorporates a groove 69.Insulating inserts 45, 46 are attached to the outer frame 38 using snapfit connections (not shown). The insulating inserts 45, 46 on the stileside of the of the pocket frame 31 may have greater depth in order toaccommodate the stile frame profile 54. Generally, the insulatinginserts 45,46 create an extended thermal conductive path where heat fromthe interior space (not shown) has to travel along the edge portion 70of the interior glass sheet 72 across the VIG conductive perimeter edge35 and then along the edge portion 70 of the exterior glass sheet 71.Typically, the width of the edge portions 70 is about two inches.

When the VIG unit 39 is in a closed position, the gaps 68 between theVIG unit 39 and the pocket frame 31 are sealed using compressible rubberseals 85. For sealing the gap 84 between the VIG unit 39 and thevertical jamb 106 of the outer frame 38, advantage is taken of theforward movement of the sliding VIG glazing assembly 39 to cause directpressure on a flexible compressible D-shaped seal 93 that wraps aroundframe stile 54. For sealing the gaps 91, 92 between the VIG unit glazingassembly 39 and the vertical split mullions 51, 52, advantage is againtaken of the sliding movement of the VIG glazing assembly 39 to causedirect pressure on two flexible wedge seals 95, 96 attached to backcorner edges 97, 98 of the mullions 51, 52 by a U-shaped plastic profile94 with extended nibs 99,100 adhered to the back face 101 of the VIGunit 39.

To form an insulating edge pocket 33 around the conductive VIG perimeteredge 35, compressible V-shaped seals 86 are attached to the inner topedges 102,103 of the insulating inserts 45, 46. Similarly to forminsulating a mullion edge pocket 89 between the mullion inserts 51, 52,compressible V-shaped seals 86 are attached to the inner top edges 104,105 of the mullion inserts 51, 52.

As shown in FIG. 3A, the VIG unit 39 is typically comprised of two glasssheets 71,72 that are separated by tiny spacers 53 that are almostinvisible to the human eye. The cavity 73 between the glass sheets 71,72 is evacuated and a getter (not shown) absorbs any trace amounts ofgas remaining. At the VIG perimeter edge 35, the space between the glasssheets 71, 72 is sealed, typically with ceramic frit material 55 that isimpermeable. By creating a hard vacuum within the VIG unit 39,conductive and convective heat transfer across the cavity 73 is largelyeliminated. The major remaining source of heat loss is through radiativeheat transfer and by incorporating an ultra-low emissivity coating 75 onone of the cavity glass surfaces 76, 77 of the VIG unit 39 thisradiative heat loss is minimized. To protect the VIG perimeter edges 35from damage, sealant 90 can be applied in the outward facing perimeterchannel 83 with silicone sealant being a suitable material. Theperimeter edges 35 of the VIG units 39 can be further protected fromaccidental damage by means of rubber bumpers (not shown).

FIG. 4 shows a vertical bottom edge cross section detail on a line 2 b-2b of the fenestration assembly 25 as shown in FIG. 2. The VIG unit 39 issupported at quarter points by a ball bearing roller cart 110 that movesback and forth in a groove 69 located in the center of the outer frame38. Compressible rubber seals 111, 112 located at the inner top edges102,103 of the insulating inserts 45, 46 seals the gaps 68 between theVIG unit 39 and the insulating inserts 45, 46. To provide an effectiveseal and to allow the VIG unit 39 to easily slide back and forth, flocktapes 126 are laminated to the front edge 109 of the compressible rubberseals 111,112.

FIG. 5 shows a vertical bottom edge cross section detail on a line 2 c-2c of the fenestration assembly 25 as shown in FIG. 2. Insulating wallpanels 36, 37 are attached to the outer frame 38. To help prevent heatloss across the cavity 29, one of the cavity wall surfaces 113 iscovered by foil 80 with a low-emissivity surface finish 81.

As shown in FIGS. 3, 4, and 5 compressible seals 85 are in most casesattached to the outer frame 38, the insulating inserts 45, 46 and theinsulating mullions 51, 52. Alternatively, the compressible seals 85 canbe attached to the glass assembly 27, particularly for the seals on thevertical insulating inserts 114,115 and mullion inserts 51, 52, this hasthe advantage that if the compressible seals 85 become dirty and as theglazing assembly 27 moves in and out of the cavity pocket 29, any dirton the compressible seals 85 does not dirty the glass surfaces one 116or four 117 (glass surfaces numbered from the exterior).

FIG. 6 shows a perspective view of the ball bearing roller cart 110 usedfor supporting the horizontal sliding glazing assembly 27. As shown inFIG. 6, the glazing assembly 27 is a conventional insulating glass unit118 that is conventionally supported on rubber setting blocks 123.Generally two wheel carts 110 are used to support the insulating glassunit 118 and as with conventional installation practice for supportinginsulating glass units with rubber setting blocks, two wheel carts 110are located at quarter points on the bottom edge 124 of the insulatingglass unit 118. In order to spread out the weight of the insulatingglass unit 118 over a larger area, the roller cart 110 typicallyincludes two or more ball bearing supports. 125. To ensure there is nota thermal bridge at the perimeter edge 122 of the insulating glass unit118, the cart 110 is made from a low conductive thermoplastic materialand is typically manufactured using an injection molding process.

FIGS. 7a,7b,7d show alternative vertical plan and bottom edge crosssection details of the push- over operation for a horizontal sliding VIGunit 39 as shown in FIG. 1. As previously mentioned, compressible rubberseals 85 laminated with flock tapes 106 are conventionally used for asliding automotive side windows seals. However our experience has shownthat these flock tape compressible rubber seals do not work aseffectively in providing sliding seals for horizontal sliding glassassemblies 25 as described in FIG. 1. There are a number of reasons whyautomotive sliding seal technology is not appropriate for buildingapplications, including: larger window sizes, less rigid glass and frameassemblies, lower manufacturing tolerances and longer required productlife. As shown in FIGS. 7a,7b,7c,7d , an alternative approach has beendeveloped where the VIG unit 39 moves over perpendicularly by about an ⅛inch to fully compress the compressible rubber seals 93 located adjacentto the inner top edges 102 of the fixed or removable insulating inserts45,46.

FIG. 7a shows a top plan view of the top or bottom profiles 128, 129 ofthe outer frame 38. The bottom or top profiles 128,129 include a flatchannel 130 that holds in place a plastic insert 131. The insert 131incorporates a single groove 69 that allows the ball bearing roller cart110 to move back and forth parallel to the side face 132 of the outerframe 38. The VIG unit 39 is bottom and top supported at quarter pointsby spring mounted hardware attached to roller carts 110.

FIG. 7b shows a vertical bottom edge cross section on a line 7 a-7 a ofthe VIG unit 39 located on the center line 133 of the edge pocket 34supported by a roller cart 110. The gaps 68 between the VIG unit 39 andthe insulating inserts 45, 46 are sealed, using three different types ofcompressible seals. The gap 135 between the VIG unit 39 and theremovable insulating insert 46 is sealed using a D-shaped compressiveseal 93. The gap 136 between the VIG unit 39 and the fixed insert 45 issealed using a double flexible V-shaped fin seal 134. In addition, a nibseal 137 provides constant perpendicular pressure on the VIG unit 39.The nib seal 137 can be made using a harder durometer rubber but asshown by arrow 138, in order to ensure that a constant perpendicularpressure is applied over an extended period of time, the nib seal 137can also incorporate a series of small metal spiral springs (not shown)or other devices that provide for long term spring-back performance. Thenib seal 137 also incorporates a front edge contact surface 127 thatprovides for minimum friction between the VIG unit 39 and the nib seal137 with one option being a flock tape surface finish 126.

FIG. 7c shows a plan detail view of the top or bottom profiles 128,129of the outer frame 38. The plastic insert track 131 incorporates awedge-shaped switch indent 139 located on the outer edge of the groove.The switch indent 139 functions somewhat similar to a railway switchpoint where the switch point can divert a train from the main track to asiding. As the VIG unit 39 travels down the groove 69, the ball bearingroller cart is pushed over by the pressure of the spring reinforced nib137. As a result, the VIG unit 39 moves perpendicular by about ⅛ of aninch 125 and the D-shaped seal 93 is fully compressed.

Typically, the insert 131 is made from rigid thermoplastic material withnylon being a suitable material because of its wear resistance, loadbearing capabilities and low coefficient of friction. The wedge shapedindents 139 can be CNC machined or alternatively, insert strip pieces(not shown) incorporating the wedge-shaped indent 139 can be injectionmolded and connected together with straight insert strip extrusions (notshown).

FIG. 7d shows a vertical cross section of the top or bottom profiles128,129 with a VIG unit 39 supported by a roller cart 110 and locatedabout ⅛″ over from the center line 133 of the top or bottom edge pockets32, 34. As a result of the perpendicular pressure applied 138, theD-shaped compressive seal 93 is fully compressed providing a highperformance air barrier seal or water shedding seal 141. The flexibleV-shaped seal 134 extends upwards to provide an air flow seal 153 thathelps prevent air flow around the bottom perimeter edge 35 of the VIGunit 39. Finally the nib seal 137 extends outwards continuing to putpressure on the bottom edge-of- glass portion 70 and providing a secondhigh performance barrier seal 142.

FIG. 8 shows a horizontal cross-section of the VIG unit 39 and thepocket frame opening 26. Both a frame stile U-shaped plastic profile 143and a cavity stile plastic profile 144 are structurally adhered to thevertical perimeter edges 145,146 of the VIG unit 39. Both the framestile 143 and the cavity stile 144 incorporate a wedge-shaped profile147 on the outer side 148 of the fenestration assembly 25. Complementaryhard rubber wedge-shaped seals 158,159 are attached to the fixedinsulating insert 45 and the fixed mullion insert 51.

Simultaneously, with the bottom and top horizontal edges (not shown) ofthe VIG unit 39 being moved over perpendicularly by about ⅛″, the VIGvertical edges 149,150 are also both simultaneously moved overperpendicularly by about ⅛″ shown by arrows 151. Both the compressibleD-shaped rubber seals 93 attached to the removable insulating insert 46and the removable mullion insert 52 are fully compressed providing highperformance barrier seals 141. The inner V-shaped flexible seals 107 arecompressed down while the outer V-shaped seals 108 expand outwards tomaintain soft air-flow seals 153 between the inner top edges 102,104 ofthe outer fixed insulating insert 45, the outer fixed insulating mullioninsert 51 and the VIG unit 39.

A tubular metal extension piece 154 with a flat metal circular head 155is attached to the back edge 156 of the frame stile profile 143 and acomplementary latch 157 is attached to the removable insulating insert46 and the outer frame 38. To lock the fenestration assembly 25, thelatch 157 engages the metal extension piece 154. The latch may be arotary cam lock that can be operated automatically by a separate smallmotor (not shown). Because the seal compression function is separatefrom the window-locking function, the process is generally easier toautomate.

Typically, the VIG unit 39 moves to a closed position and the operationof the cam locks is then automatically initiated with the VIG unit 39locked in position. When opening the locks, this process is obviouslyreversed. A further component of the hardware system is the pull handle157 that is typically directly attached to glass surface four 117 of theVIG unit 39. For the design of the handle design 157, there is generallya need to trade off the key design requirement for a comfortableergonomic user interface against a second key requirement which is tohide the VIG unit 39 in the cavity pocket 29 when the VIG unit 39 is inan open position.

FIG. 9 shows a series of vertical cross sections of the fenestrationassembly 25 as shown in FIG. 1 overlapping an existing traditionaldouble hung window 161 and installed on the interior side 56 of anexisting masonry wall 162. A top supported Venetian blind 164 may beinstalled between the fenestration assembly 25 and the traditionaldouble hung window 160. The three fenestration components 39, 160 and164 are positioned in different seasonal modes of operation.

As shown in FIG. 9a , during the winter heating season, the double hungwindow 160 is fully closed and the slats of the Venetian blinds 164 areopen at the appropriate angle to allow sunlight 169 to pass throughduring the day. Depending on the availability of solar thermal energyand the exterior outdoor temperatures, the VIG unit 39 is also typicallyfully closed.

The fenestration assembly 25 is installed over the existing window 160and is typically supported in part either by a wood stud wall (norshown) fabricated from 2″×2″ wood studs or alternatively, directlyattached to the existing wall 162 using mounting brackets (not shown).Additional wall insulation 163 is also retrofitted to the existing wall162 and the width of this additional insulation 163 typically matchesthe width 161 of the fenestration assembly 25.

Various alternative wall insulating materials can be added, including:sprayed polyurethane foam, rigid foam sheets, aerogel, rock wall,fiberglass etc. As shown in vertical cross section detail FIG. 9e oneoption is to use VIP panels 65 as the additional insulation because oftheir high insulating performance, As previously described, the minimumwidth 161 of the fenestration assembly 25 incorporating a VIG unit 39 isabout 2 inches or 2.25″ with pre applied plaster board 87 covering thecavity pocket 29.

As shown in FIG. 9e in order to match this minimum width 161, the VIPwall assembly 165 typically consists of a 1 inch VIP panel 65 withprotective metal sheeting 63, 1 inch wide protective foam material 166and 0.25″ wide pre applied plaster board 87 and in combination, this VIPwall assembly 165 has an insulating performance in excess of R-40.

For masonry walls because of the need for inward drying, the retrofit ofVIP panel assemblies 165 can cause interstitial condensation and otherrelated problems and special installation details are required. Howeverwhen adding additional insulation to an existing wood stud wall or to abrick cavity wall, there is not the same critical need for inward dryingand interior VIP panel retrofits are a more practical solution.

When retrofitting the fenestration assembly 25 to a heritage building,the traditional wood trim 167 is first removed. The fenestrationassembly and the additional wall insulation 163 is then retrofitted andplaster board 87 is then installed over both the additional insulation163 and the pocket frame 31 portion of the fenestration assembly. Thetraditional wood trim 167 is then replaced and for the casual observer,it would be difficult to notice that the building's interior appearancehad been modified. Because the perimeter edges 35 of the VIG unit 39 areburied within the insulating wall assembly 165, only transparent glass168 is visible and so the retrofit of the fenestration assembly 25 isquite visually unobtrusive. However, the combined retrofit of the VIGfenestration assembly 39 and additional insulation 163 radicallyimproves the insulating performance of the existing wall 162.

As shown in vertical cross section detail FIG. 9f , the VIG unit 39incorporates an ultra-low emissivity coating 75 positioned on glasssurface five 170. Typically, this coating functions as a solar controllow-e coating 171. Because the solar control coating 171 limits thetransfer of near infra-red solar radiation, the inner glass sheet 172heats up and as there is limited heat transfer back across the vacuumcavity 73, a surprisingly high percentage of potential solar heat gainsare re-radiated from glass surface six 173 and enter the room interiorto be usefully employed for space heating.

As shown in cross section detail FIG. 9b , during the winter night, theVenetian blinds 164 are typically closed creating two additional airspaces 174,175. As further shown in FIG. 9f , the slats 176 of theVenetian blinds 164 feature a low-emissivity coating surface finish 81or alternatively exterior coatings 177 can be installed on glasssurfaces two 76 (not shown) and glass surface three 77. With additionalexterior low-e coating 177 on surface six 173, the combined center-of-glass insulating performance for the three components 160, 164, 39can be about R-22.

As shown in FIG. 9c , during the spring/fall swing seasons as well asduring summer nights, the existing double hung window 160 is fully open:the Venetian blinds 164 are retracted, and the VIG unit 39 is in a fullyopen position within the cavity pocket 29 (See dotted sectional line182). As shown by arrow 178, maximum advantage is taken of naturalventilation and cooling.

As shown in FIG. 9d , during the summer cooling season, the existingdouble hung window 160 is opened top and bottom; the Venetian blind 164and the VIG unit 39 are both in a closed position. With the solarcontrol low-e coating 171 on glass surface five 170, there is thepotential for high solar gains to be transferred to the interior.However because the Venetian blind 164 is located on the exterior sideof the VIG unit 39 and with the slats 176 tilted at an appropriate anglemost of the direct solar radiation is intercepted and as shown by arrows179, the rejected solar gains 180 are removed by natural convectionthrough the top opening 181 of the double hung window 160.

The above has described a fenestration assembly comprising a frame thathas an opening and a pocket section. The pocket section is covered withan insulating panel. A sliding glass assembly can be received within theopening and can slide into the pocket section. The above describedfenestration assembly is well suited for use in retrofitting existingbuildings to improve insulating window-and-wall performance. Forexample, the fenestration assembly can be installed on the inside oroutside of a building to cover an existing window. The fenestrationassembly having a single sliding glass assembly may also be used in newconstruction. Further as described below, it is possible to provide twosliding glass assemblies in the frame of the sliding glass assembly. Afenestration assembly having two assemblies can be used on new orretrofit construction and provides for substantially improvedwindow-and-wall insulating performance.

FIG. 10 shows an interior elevation view of a fenestration assembly 25installed within a wood stud wall 187 (not shown) covered by plasterboard 87. Insulating trim 182 is installed over the removable insulatinginserts 46 (not shown) and outer frame 38 (not shown). The fenestrationassembly 25 incorporates a pocket frame 31 (not shown) and twohorizontal sliding, glass assemblies 27 that move back and forth intotwo cavity pockets 29,183 (not shown) that form part of the pocket frame31. Different types of horizontally sliding glass assemblies 27 can beinstalled within the fenestration assembly 25 and as shown in FIG. 10,the glass assemblies 27 are conventional sash windows 185 incorporatingconventional double glazed insulating glass units 186.

Specifically as shown in FIG. 10, the outer sash 191 is in a fullyclosed position and the inner sash 190 is in a fully open position asshown by dotted line 223. By overlapping the pocket frame 31 (notshown), only transparent glass 168 is visible. By installing the windowtrim 182 on site, it is feasible to customize the appearance of thefenestration assembly 25 both on the building exterior (not shown) andon the building interior 181.

FIG. 11 shows a vertical cross section detail of the bottom edge of thefenestration assembly 25 on a line 10 a-10 a as shown in FIG. 10installed within a 2″×6″ wood stud wall 187 with overlapping rigidinsulation 188. The insulating glass units 186 are supported in L-shapedsash frames 189 that can be made from a variety of different insulatingmaterials. As shown FIG. 11, the sash frame 189 is made from a pultrudedfiberglass profiles and the sash frame may be supported by a ballbearing roller cart 110. The outer frame 38 is also fabricated frompultruded fiberglass profiles and features two flat channels 130 thatincorporate an insert 131 (not shown).

Through the use of a compression sealing and push over mechanism, thesash windows 185 can be moved over perpendicularly by about a ⅛″. For adouble, double glazing assembly 184, when the sash windows 185 areclosed, the inner sash 190 moves perpendicular and ⅛″ closer to theinterior side 56 of the insulating wall 192 and the outer sash 191 movesabout an ⅛″ closer to the exterior side 57 of the insulating wall 192.The inner and outer compressible foam rubber seals 193,194 are fullycompressed and as a result an effective air barrier seal 195 is formedon the interior side 56 and an effective water shedding seal 196 isformed on the exterior side 57.

Two flexible V-shaped compressible seals 86 are attached to the centerinsert 197 and as the sash windows 185 move perpendicularly away fromthe center insert 197, the flexible seals 86 expand outwards to providefor an effective convective air flow barrier 153 on either side of thecenter insert 197.

In describing the insulating wall assembly 198 from inside to outside,the assembly 198 for the 2″ by 6″ stud wall 187 is comprised of thefollowing materials: 0.5″ wide plaster board 87; a vapor/air barrier 195typically a polyethylene sheet 199; 5.5 inches of fiberglass battinsulation 200; 0.5″ wood sheathing 201; a water resistance barrier 202typically bitumen coated building paper 203; rigid foam insulation 188typically 2 to 6 inches in width, and an exterior surface finish 205that functions as the water shedding barrier 196. Various exteriorsurface finishes 205 can be used, including siding and as shown in FIG.11, an Exterior Finishing Insulating System (EIFS) stucco finish 206 isdirectly applied to the rigid foam insulation 188.

Because the pocket frame 31 is buried within the insulating wallassembly 198, conventional rain screen detailing is employed to preventany water that bypasses the rain shedding barrier 196 from causingpossible water damage to the wood stud wall assembly 187. The back face207 of the rigid foam insulation 188 incorporates vertical grooves 208that allow water to be drained away to the exterior. In addition, thewater resistance barrier 202 also typically overlaps the bottom wallflashing (not shown).

In installing the fenestration assembly 25 within an insulating wallassembly 198, various other rain screen details are used to preventwater from entering the wood stud wall assembly 187, including: woodsill membrane flashings 209, corner membrane flashings (not shown) andjamb membrane flashings (not shown). In addition, a metal angle 210 isalso typically installed in line with the inner face 211 of the woodstud wall 187. The sill membrane 209 is wrapped over the metal angle 210to provide a 2″ high protective barrier that can withstand duringextreme driving rain conditions. To further enhance water drainage, asloped wood sub sill (not shown) can be installed with the sill membrane209 applied on top of the sub-sill.

The pocket frame 31 is conventionally installed using shims 213 and theinterior and exterior joints 214, 215 between the wall assembly 198 andthe pocket frame 31 are carefully sealed using sealant. To furtherensure that water sheds away from the fenestration assembly 25, aseparate overlapping foam sloped sill 216 incorporating a lower dripchannel 217 is installed on top of the rigid foam wall insulation 188.The outer insulating insert 45 is fixed in position while the tworemovable inserts 46 allow for the replacement of the insulating glass(IG) units 186 in case of glass breakage or IG edge seal failure. Arubber tape membrane 219 overlaps the sill membrane 209 applied to themetal angle 210 and is sealed to the outer face 220 of the innerremovable insert 221. The bottom edge pockets 34 are drained to theexterior using plastic tubing (not shown) with the tubing located withina groove (not shown) incorporated into the back face 207 of theinsulating foam sheet 188. At the bottom wall flashing (not shown), thetubing drains to the exterior.

By overlapping the pocket frame 31 on all four sides with rigid foaminsulation 188, heat loss through the outer frame 38, the edge pocketsand the mullion pocket is substantially reduced. Even though the foaminsulation 188 overlaps the pocket frame 31, it is feasible throughcareful rain screen detailing to prevent any wind driven water fromcausing any damage to the insulating wall assembly 198.

FIG. 12 shows a vertical cross section a line 10 b-10 b of thefenestration assembly 25 as shown in FIG. 10 installed within 2″ by 6″wood stud wall 187 with overlapping rigid insulation 188. Thefenestration assembly 25 features an outer frame 31 and two outer andinner pocket cavities 225,226 that are defined by three insulatingstressed skin panels 227,228, 229. An air/vapor barrier 195 typically apolyethylene sheet 119 overlaps the wood stud wall 197 and thefenestration assembly 25. Plaster board 87 is installed on the interiorsurface 56 of the insulating wall assembly 198 and the pocket frame 31with the option of preapplying the plaster board 87 to the innerstressed skin panel 229.

The outer stressed skin panel 227 is fixed in position and the joints 64between the outer panel 227 and the outer frame 38 are sealed with arubber membrane tape 219. A water resistant barrier 202 such as bitumencoated building paper 203 is applied to the exterior side of both theinsulating wall assembly 198 and the pocket frame 31. The wood stud wall187 is further protected by a rubber membrane 209 applied to the woodsill plate 204 and the metal angle 210 with the joints 64 between theinner stressed skin panel 229 and the outer frame 31 also sealed with arubber membrane tape 219 that also overlaps the membrane 209 applied tothe L-shaped metal angle 210.

Instead of using L-shaped sash frames 189 and conventional double glazedunits 186, VIG units 39 can be substituted. Because of the thin width ofthe VIG units 39, the width of the pocket frame 31 can be reduced to 4″and this has the advantage that a double, double VIG fenestrationassembly 230 can be installed within conventional 2″ by 4″ wood studwalls (not shown). To achieve a minimum 4″ pocket frame width, the widthof the pocket cavities 225,226 can be reduced to 0.75″, the inner andouter stressed skin foam panels 227,229 can be reduced to 1″ in width,and the center panel 228 can also be reduced to 0.5″ in width with thecenter panel 228 also typically incorporating a VIP assembly 65.

In North America, the majority of existing wood-framed residentialbuilding are fabricated using 2″ by 4″ wood stud construction and eventhough existing wood stud walls typically incorporate three and a halfinches of fiberglass insulation (R-12 approx), the combined overallinsulating performance of the window-and-wall assembly may be as littleas R-7 because of thermal bridges in the insulating wall constructionand the poor performance of the existing windows.

To radically upgrade the energy efficiency of these existing residentialbuildings, the existing windows can be removed and the openings enlargedallowing for the retrofit of double, double VIG horizontal slidingwindows 230. As much as six inches of additional rigid foam insulationcan be retrofitted on the outside of the building r with a new exteriorsurface finish then being applied. Compared to the R-7 overall thermalperformance of an existing window/wall assembly, the thermal performanceof the upgraded window-and-wall assembly can be as high as R-35 overall.

FIGS. 13a, 13b, 13c and 13d show a series of diagrammatic vertical crosssections of the double, double sash window fenestration assembly 184shown in FIGS. 10, 11 and 12. The fenestration assembly 25 comprises apocket frame 31, two horizontally sliding sash windows 232, 233incorporating conventional insulating glass units 186 that can bereceived in two insulating cavity pockets 29 (not shown), and a topsupported Venetian blind 164 deployed between the two sash windows 232,233.

FIG. 13a shows the fenestration assembly 184 during winter daytimeoperation when solar thermal energy is usefully available for heating.To allow for high solar gains, the outer sash window 232 is in a fullyclosed position and the inner sash window 233 is in a fully openposition. The outer sash window 232 incorporates a conventionalinsulating glass unit 186 with a solar gain low-e coating 234 located onglass surface three 77 as numbered from the exterior. The slats 176 ofthe Venetian blind 164 are angled to allow in solar heat gains as shownby arrow 236.

FIG. 13b shows the fenestration assembly 184 during winter night timeoperation. To provide for maximum insulating performance both the innerand outer sash windows 232, 233 are in a fully closed position. TheVenetian blind 164 is also deployed with the slats 176 being closedposition and this effectively creates two additional glazing cavities174,175. Additional low-e coatings 81 are located on either bothsurfaces of the Venetian blind slats 176 or incorporated as exteriorlow-coatings 177 on glass surfaces four 117 or five 170. With anadditional exterior low-e coating 177 on glass surface eight 235, thecombined center-of-glass insulating performance of the fenestrationassembly 184 is about R-15.

FIG. 13c shows the fenestration assembly 184 during summer night timeoperation when natural cooling is available and also during swing seasonoperation when natural ventilation is required. To maximize naturalventilation and cooling, the Venetian blind 164 is in a raised positionand both the outer and inner sash windows 232,233 (not shown) are in anopen and parked position. The air flow of natural ventilation is shownby arrow 238.

FIG. 13d shows the fenestration assembly 184 during summer day timeoperation when air conditioning is required because of high outside airtemperatures and humidity levels. To minimize solar gains, the outersash 232 is in a fully open position and the inner sash 233 is in afully closed position. A solar control low-e coating 171 is located onglass surface six 173 of the fenestration assembly 184. The Venetianblind 164 is deployed with the slats 176 angled to directly interceptmost of the incoming direct solar radiation as shown by arrow 237 with asolar control low-e coating 171 located on glass surface six 173,further preventing the transfer of near infra-red solar radiation to thebuilding interior 181.

Although window sashes incorporating conventional insulating glazingunits are shown in FIG. 13, horizontally sliding double, double VIGassembly 230 can be substituted. For winter night performance, thecombined center-of-glass insulating performance can be in excess of R-35which is substantially higher than existing commercially availableproducts.

FIG. 14 is a schematic cross section diagram of a building energy system241 that is comprised of the following major components or subsystems: ahigh-R insulating and airtight building envelope 242; a set of dynamic,high-R fenestration assemblies 243; an integrated mechanical system 244including a heat pump 245 and cold and hot storage tanks 246,247; aseries of radiant heating and cooling panels 248; an air stratifiedventilation system 249 and a control system 250 including sensors 251.Other optional system components include: a drain water heat recoverysystem 252 integrated with ground storage 253; a supply water preheattank 254, and a liquid desiccant dehumidifier and ventilation air heatexchanger 255.

Specifically, FIG. 14 shows a cross section of a perimeter room 259featuring a high-R building envelope 242 and dynamic, high-Rfenestration assemblies 243, typically with R-35 minimum performance.The dynamic, high-R fenestration assembly 243 is comprised of a pocketframe 31, horizontal sliding double, double VIG units 230 and with aVenetian blind 164 located between the VIG units 39.

As previously described in FIG. 13, the VIG units 39 and the Venetianblind 164 can be deployed in various ways to optimize heating andcooling performance. Although a double, double VIG assembly 230 is shownin FIG. 14, alternative dynamic, high-R window technologies can besubstituted and these technologies also feature moveable insulation,variable solar control and natural ventilation.

The integrated mechanical system 244 includes a cold thermal storagetank 246, a hot thermal storage tank 247 and a heat pump 245 that canfunction in either in a single or dual mode of operation. In the singlemode of operation, the heat pump 245 upgrades low grade thermal heat orcold from various sources such as passive solar heat, supply waterpreheat and drain water heat recovery.

In the dual mode of operation, the heat pump 245 transfers heat from thecold water storage tank 246 to the hot water tank 247. As the heat pump245 simultaneously supplies both hot and cold water and assuming thatboth the hot and cold water can be usefully utilized, this dual mode ofoperation is intrinsically more energy efficient than if only hot orcold water is solely produced and utilized. Although not shown in FIG.14, one option is for the hot and cold tanks 246,247 to be combined intoa single stratified tank (not shown) and for the single tank to bemanufactured from an insulating material such as fiberglass.

The integrated mechanical system 244 also incorporates a liquid handlingsystem 256 that includes a control system, a series of three way valves,pump and related components. The liquid handling unit 256 allows theintegrated mechanical system 244 to efficiently change over from dualmode to single mode operation.

With a high-R building envelope 241 and dynamic, high-R energy efficientwindows 243, the space heating and cooling loads of a building are sosmall that it is preferable because of air quality concerns, thatheating and cooling inputs are supplied separately from ventilation air.As shown in FIG. 14, one solution for separating heating and coolinginputs from ventilation air is to use hydronic radiant panels 248 thatare integrated into the room ceiling 257 and are typically covered by acomparatively high thermal mass building material such as plaster board87.

Hydronic radiant panels 248 offer the key advantage that both radiantheating and cooling can be delivered through the same hydronicdistribution system 262. Also the radiant panels 248 connected to ahydronic distribution system 262 allow comfort conditions to becontrolled room by room. Typically during the winter heating season, theradiant hydronic ceiling panels 248 are connected to the hot water tank247 and during the summer cooling season, the radiant hydronic ceilingpanels 248 are connected to the cold thermal storage tank 246.

By eliminating window down drafting, dynamic, high-R fenestrationassemblies 243 provide the opportunity to use air stratified ventilation249. With air stratified ventilation 249, ventilation supply air asshown by arrows 258 enters the perimeter room 259 through lower vents272. The air enters at a low velocity and a temperature only slightlylower than the desired room temperature. The cooler supply air displacesthe warmer room air creating a zone of fresh air at the occupied level.Heat and contaminants produced by the room occupants and theiractivities rise to the ceiling 257. The polluted air 261 is then fullyexhausted from the perimeter room 259 through upper vents 273.

Air stratified ventilation 249 only uses buoyancy to supply ventilationair and typically, good air quality can be maintained without the needfor mechanical exhaust fans. However as shown in FIG. 14, there is theoption of using a small duct fan 261 to speed up the removal of pollutedor high humidity air from the perimeter room 259.

One key advantage of a stratified air ventilation system 249 is that inhot, humid climates, an air stratified system 249 is more efficient indrying out a building than a centralized ducting system. As a result,dry comfort conditions can be more quickly achieved and this allows formore aggressive intermittent use of natural ventilation (i.e. openwindows).

To provide dry air to the perimeter room 259, a solution is to use aliquid desiccant dehumidifier 255 that typically uses waste heat fromthe building to regenerate the liquid desiccant material. In the winter,the liquid desiccant dehumidifier and energy exchanger 255 recovers bothlatent and sensible heat from the ventilation exhaust air and preheatsthe incoming supply air. In the summer, the liquid desiccantdehumidifier and energy exchanger 255 dehumidifies and cools theincoming ventilation air.

In hot and humid climates, a key advantage of the liquid desiccantdehumidifier 255 is that the sensible cooling load and thedehumidification load are balanced and this allows for efficient dualmode operation of the heat pump 245. In hot, dry climates, the sensiblecooling load dominates but by spraying water droplets, the incoming aircan be cooled through evaporation and then by dehumidifying the incomingair, it is again feasible to balance heating and cooling loads thatallows for efficient dual mode operation of the heat pump 245.

To optimize the performance of the building energy system 241, there isa need for a control system 250 and as shown in FIG. 14, one approach isto incorporate an individual controller 263 in each perimeter room 259with these individual controllers 263 then linked to a centralcontroller 264. The individual room controllers 263 can control theoperation of the hydronic radiant heating and cooling panels 248, thesmall room exhaust fan 261 and the dynamic components of thefenestration assembly 243.

Each perimeter room 256 also incorporates sensors 251 that monitor arange of different properties, including: room temperature, humidity,occupancy and light levels. Additional sensors 265 located outside ofthe building enclosure monitor other properties, including: outsidetemperature and availability of solar radiation. These various sensors251, 265 are typically linked either to the room controller 263 ordirectly to the central controller 264 using wireless connections 260.

Major appliances such as a refrigerator or a clothes dryer as well asother major HVAC components of the building energy system 241 can alsobe linked to the central controller 264 by wireless connections 260. Aswell, the central controller 264 can be linked to the Internet and thelocal electrical utility company. Based on weather predictions, sensormeasurements and an understanding of the occupant's future activities,the central controller 264 can determine how much heat or cold thermalenergy needs to be stored.

Specifically for the dynamic high-R fenestration system 243, thecontrollers 263, 264 can determine room by room three key functions: 1.whether one or both VIG units 39 should be closed to reduce heat loss;2. whether the fenestration assembly 242 should be configured to collector reject solar heat gains 266, and 3. whether the VIG units should beopened to provide for natural ventilation and night time cooling 267.

Particularly with unoccupied rooms, more aggressive passive solarheating and natural ventilation/night cooling strategies can be adopted.For example during or prior to a sunny winter's day, the thermal mass inthe ceiling 257 can be cooled down by the radiant hydronic panels 248resulting in the low grade heat from the ceiling's thermal mass beingtransferred to the cold thermal storage tank 246. This low grade heatcan then be upgraded by the heat pump 245 before being stored in the hotthermal storage tank 247. As a result of lower thermal masstemperatures, solar heat gains can be more efficiently collected andstored in the thermal mass, resulting in an increased utilization ofavailable solar thermal energy 266.

With the use of a liquid desiccant dehumidifier 255 and prior to hotsummer's day, the thermal mass in the ceiling 257 can also be cooleddown by the radiant hydronic panels 248 resulting in the low grade heatfrom the ceiling's thermal mass being transferred to the cold thermalstorage tank 246. As with the winter day operation, this low grade heatcan then be upgraded by the heat pump 245 before being stored in the hotwater storage tank 247. As a result of lower thermal mass temperatures,there is a reduced need for daytime cooling with waste heat beingabsorbed into the thermal mass.

With natural ventilation and night time cooling and even when theoutside night air is comparatively warm, low grade heat can also becollected, stored and later usefully employed for liquid desiccantregeneration. The night time low grade heat gains can be collected,stored and upgrade for high temperature regeneration of the liquiddesiccant during the day when the windows are closed.

With a high-R building envelope 242 and dynamic high-R windows 243,domestic hot water (DHW) heating loads can be larger than space heatingloads. Existing drain water heat recovery devices recover heat from thewaste water from showers or clothes washing and then using a spiral heatexchanger, the devices transfer this waste heat to preheat the incomingcold water supply from a ground well or water mains. Because theseexisting heat recovery devices can only operate efficiently when watersupply and waste water production are in tandem, these existing heatrecovery devices are typically only about 25% efficient.

An alternative heat recovery strategy is for the cold water supply 268from a ground well or water mains to pass through a heat exchanger 269located in a preheat water tank 254 that is connected to the radiantceiling panels 248. As previously described during sunny winter days,the thermal mass in the ceiling 257 can be cooled down by the radianthydronic panels 248 resulting in the low grade heat from the ceilingbeing transferred to the supply water preheat tank 254. As the coldwater supply 268 passes through the preheat tank 254, it is heated up toroom temperatures using only passive solar heat gains delivered via thefenestration assembly 243.

Complementing the preheat tank 254 is a drain water heat recovery devicethat simply consists of piping wrapped around or below a buried andinsulated septic tank 271. Because the tank 271 is in thermal contactwith the ground much of the drain water waste heat is recovered andtemporarily stored in the ground 253. When required, this stored drainwater waste heat can be removed and upgraded by the heat pump 245. It isestimated that this combined system of solar preheat and heat pumpupgrade of stored drain water waste heat can provide for an overallequivalent DHW heat recovery efficiency of 75 per cent.

To simplify the on-site installation of the heating, ventilation and airconditioning (HVAC) system, component parts of the integrated mechanicalsystem 244 including the heat pump 245 and liquid handling unit 256;component parts of the control system 250 and component parts of theliquid desiccant dehumidifier 255 can be packaged in a single box withinput and output connections to other major components of the HVACsystem, including; radiant heating and cooling panels 248; hot and coldstorage tanks 247,248; supply water pre heat tank 254 and drain waterheat recovery 252 including ground storage 253.

In general as a result of combining a high-R building envelope 242 anddynamic high-R windows 243 with an integrated mechanical system 244, abuilding enclosure can be cost effectively heated and cooled using onlyelectrical power. By using a small efficient heat pump 245 for spaceheating, space cooling and domestic hot water heating, the integratedmechanical system 244 provides for a more even seasonal demand forelectrical power. Moreover because the integrated mechanical system 244incorporates both a cold water tank 246 and a hot thermal storage 247 aswell as ground linked storage 253, the building energy system 241 can beoperated so that daily peak load demands are substantially reduced andfull advantage can be taken of off-peak power rates.

Numerous modifications, variations and adaptations may be made to theparticular embodiments of the invention described above withoutdeparting from the scope of the invention which is defined in theclaims.

What is claimed is:
 1. A building energy system comprising: a building enclosure having an interior and exterior, the building enclosure comprising at least one wall separating the interior and exterior and comprising an opening; and a fenestration assembly enclosing the opening in the wall, the fenestration assembly comprising: a frame having at least four edges surrounding first and second sides to be partially covered by building material, the frame defining: an opening from the first side to the second side; and a first pocket section next to the opening and sized at least equally to the opening, the frame comprising: an insulating mullion pocket between the opening and the first pocket section; and three insulating edge pockets within edges of the frame surrounding the opening; an insulating section between the first pocket section and one of the first or second sides of the frame; and a first sliding glass assembly supported on a bottom edge by roller carts moveable within a raceway of the frame, the first sliding glass assembly capable of sealing the opening and moveable between: a fully-closed position in which the first sliding glass assembly is located substantially within the opening and seals the opening; and a fully-open position in which the first sliding glass assembly is located substantially within the first pocket section of the frame, wherein the first sliding glass assembly comprises two or more glass sheets that are spaced apart and sealed at perimeter edges of the two glass sheets and features one or more low emissivity coatings facing at least one glazing cavity between the glass sheets and where the center-of-glass provides more thermal resistance than the perimeter edges, and wherein in the fully-closed position, the perimeter edges of the first sliding glass assembly are buried within the three insulating edge pockets and the insulating mullion pocket of the frame.
 2. The building energy system of claim 1, further comprising a second fenestration assembly located in the opening and aligned with the fenestration assembly.
 3. The building energy system of claim 1, wherein the at least one wall comprising the opening is a pre-existing wall having a window previously installed in the opening, wherein fenestration assembly is installed over the previously installed window.
 4. The building energy system of claim 3, wherein the fenestration assembly is installed to the interior of the previously installed window.
 5. The building energy system of claim 4, wherein the frame of the fenestration assembly further comprises a second pocket section next to the opening and sized at least equally to the opening, the insulating section located between the first and second pocket sections, and wherein the fenestration assembly further comprises a second sliding glass assembly within the frame capable of sealing the opening and moveable between: a fully-closed position in which the second sliding glass assembly is located substantially within the opening and seals the opening; and a fully-open position in which the second sliding glass assembly is located substantially within the second pocket section of the frame.
 6. The building energy system of claim 5, further comprising: an integrated mechanical system that provides heating and cooling for various functions, and comprises: a cold thermal storage tank; a hot thermal storage tank; and a heat pump that in part transfers heat from the cold thermal storage tank to the hot thermal storage tank; one or more hydronic heating/cooling devices each at least partially covered by a material of a high thermal mass and fluidly coupled to the hot and cold thermal storage tank for heating or cooling a portion of the building enclosure, wherein during a heating season when solar thermal energy is available, one or more fenestration assemblies are operated to provide for higher solar thermal gains and the one or more hydronic devices are operated to cool down at least part of the respective thermal masses, wherein stored low grade heat within the respective thermal masses is transferred to the cold thermal storage tank and is then extracted and upgraded by the heat pump and stored in the hot thermal storage tank.
 7. The building energy system of claim 6, where the hydronic devices comprise radiant ceiling panels and the material covering the hydronic devices is plasterboard.
 8. The building energy system of claim 6, further comprising an air stratified ventilation system.
 9. The building energy system of claim 6, wherein one or more rooms of the building enclosure incorporate a small extract fan located at a high level within the room and occasionally operated to remove polluted air from the room.
 10. The building energy system of claim 6, further comprising a first actuator for controlling movement of the first sliding glass assembly between the fully-open position and the fully-closed position.
 11. The building energy system of claim 6, further comprising a second actuator for controlling movement of the second sliding glass assembly between the fully-open position and the fully-closed position.
 12. The building energy system of claim 6, further comprising a blind within opening of the frame located between the first sliding glass assembly and the second glass assembly.
 13. The building energy system of claim 12, further comprising an actuator for controlling the position of the blind.
 14. The building energy system of claim 6, wherein the respective positions of the first and second sliding glass assemblies are automatically adjusted to control solar heat gains of the building enclosure through the opening.
 15. The building energy system of claim 6, wherein one of the first or second sides of the frame is an exterior side and the other of the first or second sides of the frame is an interior side, wherein each of the glass surfaces of the first and second sliding glass assemblies are numbered sequentially starting from the exterior side and wherein glass surface two has a solar gain, low emissivity coating.
 16. The building energy system of claim 15, wherein glass surface six has a solar control, low emissivity coating.
 17. The building energy system of claim 6, wherein at least one glass surface of one or more of the first or second sliding glass assemblies comprises a solar control low emissivity coating or a solar gain low emissivity coating.
 18. The building energy system of claim 1, further comprising one or more interior sensors that measure environmental properties of the interior of the building energy system.
 19. The building energy system of claim 18, further comprising one or more exterior sensors that measure environmental properties of the exterior of the building energy system.
 20. The building energy system of claim 18, wherein the environmental properties comprise one or more of temperature, relative humidity, insolation and occupancy.
 21. The building energy system of claim 18, wherein the sensors are linked to one more controllers for controlling the respective positions of the first and second sliding glass assemblies.
 22. The building energy system of claim 21, wherein at least one of the one or more controllers are linked to the Internet.
 23. The building energy system of claim 1, further comprising a second insulating section located on the other side of the frame from the insulating section.
 24. The building energy system of claim 1, wherein the insulating section and the second insulating section each comprise a stressed skin panel comprising an insulating core and at least one structural skin.
 25. The building energy system of claim 24, wherein the insulating section and the second insulating section are covered in respective building material.
 26. The building energy system of claim 1, further comprising a liquid desiccant dehumidifier.
 27. The building energy system of claim 26, wherein the liquid desiccant dehumidifier uses heat from the building system upgraded by the heat pump to regenerate the liquid desiccant.
 28. The building energy system of claim 1, further comprising a pre-heating water tank for pre-heating water for the hot water tank.
 29. The building energy system of claim 28, further comprising one or more hydronic devices, wherein heat recovered from the one or more hydronic devices is used to pre-heat the water of the pre-heating water tank.
 30. The building energy system of claim 28, further comprising a drain water heat recovery device, wherein heat recovered from the drain water heat recovery device is used to pre-heat the water of the pre-heating water tank. 